Use message.yaml in parser.

pkg/front_end/lib/src/fasta/fasta_codes.dart

+// Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+library fasta.codes;
+
+import 'package:front_end/src/fasta/scanner/token.dart' show Token;
+
+part 'fasta_codes_generated.dart';
+
+class FastaCode<T> {
+  final String template;
+
+  final String tip;
+
+  final String analyzerCode;
+
+  final String dart2jsCode;
+
+  final T format;
+
+  const FastaCode(
+      {this.template,
+      this.tip,
+      this.analyzerCode,
+      this.dart2jsCode,
+      this.format});
+}
+
+class FastaMessage {
+  final Uri uri;
+
+  final int charOffset;
+
+  final String message;
+
+  final String tip;
+
+  final FastaCode code;
+
+  final Map<String, dynamic> arguments;
+
+  const FastaMessage(this.uri, this.charOffset, this.code,
+      {this.message, this.tip, this.arguments});
+}